Calls fixHtmlAndJs and if there's embedded script tags,
construct a function that executes the contents of the scripts
then evaluations to Expression.

Calls fixHtmlAndJs and if there's embedded script tags,
construct a function that executes the contents of the scripts
then evaluations to Expression. For use when converting
a JsExp that contains HTML.

Currently, fixHtmlFunc does not do event extraction, even when
LiftRules.extractInlineJavaScript is true, due to poor interactions
with JsExp usage. This will be fixed in a future Lift release; see
https://github.com/lift/framework/issues/1801 .